use crate::http::context::{AppContext, OpenApiResult, bad_request};
use crate::io::story_metadata::{StoryMetadata, parse_front_matter, parse_unchecked_todos};
use crate::workflow::{
    CoverageReport, StoryTestResults, TestCaseResult, TestStatus,
    evaluate_acceptance_with_coverage, parse_coverage_json, summarize_results,
};
use poem_openapi::{Object, OpenApi, Tags, payload::Json};
use serde::Deserialize;
use std::collections::BTreeSet;
use std::fs;
use std::sync::Arc;

#[derive(Tags)]
enum WorkflowTags {
    Workflow,
}

#[derive(Deserialize, Object)]
struct TestCasePayload {
    pub name: String,
    pub status: String,
    pub details: Option<String>,
}

#[derive(Deserialize, Object)]
struct RecordTestsPayload {
    pub story_id: String,
    pub unit: Vec<TestCasePayload>,
    pub integration: Vec<TestCasePayload>,
}

#[derive(Deserialize, Object)]
struct AcceptanceRequest {
    pub story_id: String,
}

#[derive(Object)]
struct TestRunSummaryResponse {
    pub total: usize,
    pub passed: usize,
    pub failed: usize,
}

#[derive(Object)]
struct CoverageReportResponse {
    pub current_percent: f64,
    pub threshold_percent: f64,
    pub baseline_percent: Option<f64>,
}

#[derive(Object)]
struct AcceptanceResponse {
    pub can_accept: bool,
    pub reasons: Vec<String>,
    pub warning: Option<String>,
    pub summary: TestRunSummaryResponse,
    pub missing_categories: Vec<String>,
    pub coverage_report: Option<CoverageReportResponse>,
}

#[derive(Object)]
struct ReviewStory {
    pub story_id: String,
    pub can_accept: bool,
    pub reasons: Vec<String>,
    pub warning: Option<String>,
    pub summary: TestRunSummaryResponse,
    pub missing_categories: Vec<String>,
    pub coverage_report: Option<CoverageReportResponse>,
}

#[derive(Deserialize, Object)]
struct RecordCoveragePayload {
    pub story_id: String,
    pub current_percent: f64,
    pub threshold_percent: Option<f64>,
}

#[derive(Deserialize, Object)]
struct CollectCoverageRequest {
    pub story_id: String,
    pub threshold_percent: Option<f64>,
}

#[derive(Object)]
struct ReviewListResponse {
    pub stories: Vec<ReviewStory>,
}

#[derive(Object)]
struct StoryTodosResponse {
    pub story_id: String,
    pub story_name: Option<String>,
    pub todos: Vec<String>,
}

#[derive(Object)]
struct TodoListResponse {
    pub stories: Vec<StoryTodosResponse>,
}

#[derive(Object)]
struct UpcomingStory {
    pub story_id: String,
    pub name: Option<String>,
}

#[derive(Object)]
struct UpcomingStoriesResponse {
    pub stories: Vec<UpcomingStory>,
}

fn load_upcoming_stories(ctx: &AppContext) -> Result<Vec<UpcomingStory>, String> {
    let root = ctx.state.get_project_root()?;
    let upcoming_dir = root.join(".story_kit").join("stories").join("upcoming");

    if !upcoming_dir.exists() {
        return Ok(Vec::new());
    }

    let mut stories = Vec::new();
    for entry in fs::read_dir(&upcoming_dir)
        .map_err(|e| format!("Failed to read upcoming stories directory: {e}"))?
    {
        let entry = entry.map_err(|e| format!("Failed to read upcoming story entry: {e}"))?;
        let path = entry.path();
        if path.extension().and_then(|ext| ext.to_str()) != Some("md") {
            continue;
        }
        let story_id = path
            .file_stem()
            .and_then(|stem| stem.to_str())
            .ok_or_else(|| "Invalid story file name.".to_string())?
            .to_string();
        let contents = fs::read_to_string(&path)
            .map_err(|e| format!("Failed to read story file {}: {e}", path.display()))?;
        let name = parse_front_matter(&contents)
            .ok()
            .and_then(|meta| meta.name);
        stories.push(UpcomingStory { story_id, name });
    }

    stories.sort_by(|a, b| a.story_id.cmp(&b.story_id));
    Ok(stories)
}

fn load_current_story_metadata(ctx: &AppContext) -> Result<Vec<(String, StoryMetadata)>, String> {
    let root = ctx.state.get_project_root()?;
    let current_dir = root.join(".story_kit").join("stories").join("current");

    if !current_dir.exists() {
        return Ok(Vec::new());
    }

    let mut stories = Vec::new();
    for entry in fs::read_dir(&current_dir)
        .map_err(|e| format!("Failed to read current stories directory: {e}"))?
    {
        let entry = entry.map_err(|e| format!("Failed to read current story entry: {e}"))?;
        let path = entry.path();
        if path.extension().and_then(|ext| ext.to_str()) != Some("md") {
            continue;
        }
        let story_id = path
            .file_stem()
            .and_then(|stem| stem.to_str())
            .ok_or_else(|| "Invalid story file name.".to_string())?
            .to_string();
        let contents = fs::read_to_string(&path)
            .map_err(|e| format!("Failed to read story file {}: {e}", path.display()))?;
        let metadata = parse_front_matter(&contents)
            .map_err(|e| format!("Failed to parse front matter for {story_id}: {e:?}"))?;
        stories.push((story_id, metadata));
    }

    Ok(stories)
}

fn to_review_story(
    story_id: &str,
    results: &StoryTestResults,
    coverage: Option<&CoverageReport>,
) -> ReviewStory {
    let decision = evaluate_acceptance_with_coverage(results, coverage);
    let summary = summarize_results(results);

    let mut missing_categories = Vec::new();
    let mut reasons = decision.reasons;

    if results.unit.is_empty() {
        missing_categories.push("unit".to_string());
        reasons.push("Missing unit test results.".to_string());
    }
    if results.integration.is_empty() {
        missing_categories.push("integration".to_string());
        reasons.push("Missing integration test results.".to_string());
    }

    let can_accept = decision.can_accept && missing_categories.is_empty();

    let coverage_report = coverage.map(|c| CoverageReportResponse {
        current_percent: c.current_percent,
        threshold_percent: c.threshold_percent,
        baseline_percent: c.baseline_percent,
    });

    ReviewStory {
        story_id: story_id.to_string(),
        can_accept,
        reasons,
        warning: decision.warning,
        summary: TestRunSummaryResponse {
            total: summary.total,
            passed: summary.passed,
            failed: summary.failed,
        },
        missing_categories,
        coverage_report,
    }
}

pub struct WorkflowApi {
    pub ctx: Arc<AppContext>,
}

#[OpenApi(tag = "WorkflowTags::Workflow")]
impl WorkflowApi {
    /// Record test results for a story (unit + integration).
    #[oai(path = "/workflow/tests/record", method = "post")]
    async fn record_tests(&self, payload: Json<RecordTestsPayload>) -> OpenApiResult<Json<bool>> {
        let unit = payload
            .0
            .unit
            .into_iter()
            .map(to_test_case)
            .collect::<Result<Vec<_>, String>>()
            .map_err(bad_request)?;
        let integration = payload
            .0
            .integration
            .into_iter()
            .map(to_test_case)
            .collect::<Result<Vec<_>, String>>()
            .map_err(bad_request)?;

        let mut workflow = self
            .ctx
            .workflow
            .lock()
            .map_err(|e| bad_request(e.to_string()))?;
        workflow
            .record_test_results_validated(payload.0.story_id, unit, integration)
            .map_err(bad_request)?;

        Ok(Json(true))
    }

    /// Evaluate acceptance readiness for a story.
    #[oai(path = "/workflow/acceptance", method = "post")]
    async fn acceptance(
        &self,
        payload: Json<AcceptanceRequest>,
    ) -> OpenApiResult<Json<AcceptanceResponse>> {
        let (results, coverage) = {
            let workflow = self
                .ctx
                .workflow
                .lock()
                .map_err(|e| bad_request(e.to_string()))?;
            let results = workflow
                .results
                .get(&payload.0.story_id)
                .cloned()
                .unwrap_or_default();
            let coverage = workflow.coverage.get(&payload.0.story_id).cloned();
            (results, coverage)
        };

        let decision =
            evaluate_acceptance_with_coverage(&results, coverage.as_ref());
        let summary = summarize_results(&results);

        let mut missing_categories = Vec::new();
        let mut reasons = decision.reasons;

        if results.unit.is_empty() {
            missing_categories.push("unit".to_string());
            reasons.push("Missing unit test results.".to_string());
        }
        if results.integration.is_empty() {
            missing_categories.push("integration".to_string());
            reasons.push("Missing integration test results.".to_string());
        }

        let can_accept = decision.can_accept && missing_categories.is_empty();

        let coverage_report = coverage.map(|c| CoverageReportResponse {
            current_percent: c.current_percent,
            threshold_percent: c.threshold_percent,
            baseline_percent: c.baseline_percent,
        });

        Ok(Json(AcceptanceResponse {
            can_accept,
            reasons,
            warning: decision.warning,
            summary: TestRunSummaryResponse {
                total: summary.total,
                passed: summary.passed,
                failed: summary.failed,
            },
            missing_categories,
            coverage_report,
        }))
    }

    /// List stories that are ready for human review.
    #[oai(path = "/workflow/review", method = "get")]
    async fn review_queue(&self) -> OpenApiResult<Json<ReviewListResponse>> {
        let stories = {
            let workflow = self
                .ctx
                .workflow
                .lock()
                .map_err(|e| bad_request(e.to_string()))?;
            workflow
                .results
                .iter()
                .map(|(story_id, results)| {
                    let coverage = workflow.coverage.get(story_id);
                    to_review_story(story_id, results, coverage)
                })
                .filter(|story| story.can_accept)
                .collect::<Vec<_>>()
        };

        Ok(Json(ReviewListResponse { stories }))
    }

    /// List stories in the review queue, including blocked items and current stories.
    #[oai(path = "/workflow/review/all", method = "get")]
    async fn review_queue_all(&self) -> OpenApiResult<Json<ReviewListResponse>> {
        let current_stories =
            load_current_story_metadata(self.ctx.as_ref()).map_err(bad_request)?;
        let stories = {
            let mut workflow = self
                .ctx
                .workflow
                .lock()
                .map_err(|e| bad_request(e.to_string()))?;

            if !current_stories.is_empty() {
                workflow.load_story_metadata(current_stories);
            }

            let mut story_ids = BTreeSet::new();

            for story_id in workflow.results.keys() {
                story_ids.insert(story_id.clone());
            }
            for story_id in workflow.stories.keys() {
                story_ids.insert(story_id.clone());
            }

            story_ids
                .into_iter()
                .map(|story_id| {
                    let results = workflow.results.get(&story_id).cloned().unwrap_or_default();
                    let coverage = workflow.coverage.get(&story_id);
                    to_review_story(&story_id, &results, coverage)
                })
                .collect::<Vec<_>>()
        };

        Ok(Json(ReviewListResponse { stories }))
    }

    /// Record coverage data for a story.
    #[oai(path = "/workflow/coverage/record", method = "post")]
    async fn record_coverage(
        &self,
        payload: Json<RecordCoveragePayload>,
    ) -> OpenApiResult<Json<bool>> {
        let mut workflow = self
            .ctx
            .workflow
            .lock()
            .map_err(|e| bad_request(e.to_string()))?;
        workflow.record_coverage(
            payload.0.story_id,
            payload.0.current_percent,
            payload.0.threshold_percent,
        );
        Ok(Json(true))
    }

    /// Run coverage collection: execute test:coverage, parse output, record result.
    #[oai(path = "/workflow/coverage/collect", method = "post")]
    async fn collect_coverage(
        &self,
        payload: Json<CollectCoverageRequest>,
    ) -> OpenApiResult<Json<CoverageReportResponse>> {
        let root = self
            .ctx
            .state
            .get_project_root()
            .map_err(bad_request)?;

        let frontend_dir = root.join("frontend");

        // Run pnpm run test:coverage in the frontend directory
        let output = tokio::task::spawn_blocking(move || {
            std::process::Command::new("pnpm")
                .args(["run", "test:coverage"])
                .current_dir(&frontend_dir)
                .output()
        })
        .await
        .map_err(|e| bad_request(format!("Task join error: {e}")))?
        .map_err(|e| bad_request(format!("Failed to run coverage command: {e}")))?;

        if !output.status.success() {
            let stderr = String::from_utf8_lossy(&output.stderr);
            return Err(bad_request(format!("Coverage command failed: {stderr}")));
        }

        // Read the coverage summary JSON
        let summary_path = root
            .join("frontend")
            .join("coverage")
            .join("coverage-summary.json");
        let json_str = fs::read_to_string(&summary_path)
            .map_err(|e| bad_request(format!("Failed to read coverage summary: {e}")))?;

        let current_percent = parse_coverage_json(&json_str).map_err(bad_request)?;

        // Record coverage in workflow state
        let coverage_report = {
            let mut workflow = self
                .ctx
                .workflow
                .lock()
                .map_err(|e| bad_request(e.to_string()))?;
            workflow.record_coverage(
                payload.0.story_id.clone(),
                current_percent,
                payload.0.threshold_percent,
            );
            workflow
                .coverage
                .get(&payload.0.story_id)
                .cloned()
                .expect("just inserted")
        };

        Ok(Json(CoverageReportResponse {
            current_percent: coverage_report.current_percent,
            threshold_percent: coverage_report.threshold_percent,
            baseline_percent: coverage_report.baseline_percent,
        }))
    }

    /// List unchecked acceptance criteria (TODOs) for all current stories.
    #[oai(path = "/workflow/todos", method = "get")]
    async fn story_todos(&self) -> OpenApiResult<Json<TodoListResponse>> {
        let root = self.ctx.state.get_project_root().map_err(bad_request)?;
        let current_dir = root.join(".story_kit").join("stories").join("current");

        if !current_dir.exists() {
            return Ok(Json(TodoListResponse {
                stories: Vec::new(),
            }));
        }

        let mut stories = Vec::new();
        let mut entries: Vec<_> = fs::read_dir(&current_dir)
            .map_err(|e| bad_request(format!("Failed to read current stories: {e}")))?
            .filter_map(|e| e.ok())
            .collect();
        entries.sort_by_key(|e| e.file_name());

        for entry in entries {
            let path = entry.path();
            if path.extension().and_then(|ext| ext.to_str()) != Some("md") {
                continue;
            }
            let story_id = path
                .file_stem()
                .and_then(|stem| stem.to_str())
                .unwrap_or_default()
                .to_string();
            let contents = fs::read_to_string(&path)
                .map_err(|e| bad_request(format!("Failed to read {}: {e}", path.display())))?;
            let story_name = parse_front_matter(&contents)
                .ok()
                .and_then(|m| m.name);
            let todos = parse_unchecked_todos(&contents);
            stories.push(StoryTodosResponse {
                story_id,
                story_name,
                todos,
            });
        }

        Ok(Json(TodoListResponse { stories }))
    }

    /// List upcoming stories from .story_kit/stories/upcoming/.
    #[oai(path = "/workflow/upcoming", method = "get")]
    async fn list_upcoming_stories(&self) -> OpenApiResult<Json<UpcomingStoriesResponse>> {
        let stories = load_upcoming_stories(self.ctx.as_ref()).map_err(bad_request)?;
        Ok(Json(UpcomingStoriesResponse { stories }))
    }

    /// Ensure a story can be accepted; returns an error when gates fail.
    #[oai(path = "/workflow/acceptance/ensure", method = "post")]
    async fn ensure_acceptance(
        &self,
        payload: Json<AcceptanceRequest>,
    ) -> OpenApiResult<Json<bool>> {
        let response = self.acceptance(payload).await?.0;
        if response.can_accept {
            return Ok(Json(true));
        }

        let mut parts = Vec::new();
        if !response.reasons.is_empty() {
            parts.push(response.reasons.join("; "));
        }
        if let Some(warning) = response.warning {
            parts.push(warning);
        }

        let message = if parts.is_empty() {
            "Acceptance is blocked.".to_string()
        } else {
            format!("Acceptance is blocked: {}", parts.join("; "))
        };

        Err(bad_request(message))
    }
}

fn to_test_case(input: TestCasePayload) -> Result<TestCaseResult, String> {
    let status = parse_test_status(&input.status)?;
    Ok(TestCaseResult {
        name: input.name,
        status,
        details: input.details,
    })
}

fn parse_test_status(value: &str) -> Result<TestStatus, String> {
    match value {
        "pass" => Ok(TestStatus::Pass),
        "fail" => Ok(TestStatus::Fail),
        other => Err(format!(
            "Invalid test status '{other}'. Use 'pass' or 'fail'."
        )),
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::workflow::{StoryTestResults, TestCaseResult, TestStatus};

    #[test]
    fn parse_test_status_pass() {
        assert_eq!(parse_test_status("pass").unwrap(), TestStatus::Pass);
    }

    #[test]
    fn parse_test_status_fail() {
        assert_eq!(parse_test_status("fail").unwrap(), TestStatus::Fail);
    }

    #[test]
    fn parse_test_status_invalid() {
        let result = parse_test_status("unknown");
        assert!(result.is_err());
        assert!(result.unwrap_err().contains("Invalid test status"));
    }

    #[test]
    fn to_test_case_converts_pass() {
        let payload = TestCasePayload {
            name: "my_test".to_string(),
            status: "pass".to_string(),
            details: Some("all good".to_string()),
        };
        let result = to_test_case(payload).unwrap();
        assert_eq!(result.name, "my_test");
        assert_eq!(result.status, TestStatus::Pass);
        assert_eq!(result.details, Some("all good".to_string()));
    }

    #[test]
    fn to_test_case_rejects_invalid_status() {
        let payload = TestCasePayload {
            name: "bad".to_string(),
            status: "maybe".to_string(),
            details: None,
        };
        assert!(to_test_case(payload).is_err());
    }

    #[test]
    fn to_review_story_all_passing() {
        let results = StoryTestResults {
            unit: vec![TestCaseResult {
                name: "u1".to_string(),
                status: TestStatus::Pass,
                details: None,
            }],
            integration: vec![TestCaseResult {
                name: "i1".to_string(),
                status: TestStatus::Pass,
                details: None,
            }],
        };

        let review = to_review_story("story-29", &results, None);
        assert!(review.can_accept);
        assert!(review.reasons.is_empty());
        assert!(review.missing_categories.is_empty());
        assert_eq!(review.summary.total, 2);
        assert_eq!(review.summary.passed, 2);
    }

    #[test]
    fn to_review_story_missing_integration() {
        let results = StoryTestResults {
            unit: vec![TestCaseResult {
                name: "u1".to_string(),
                status: TestStatus::Pass,
                details: None,
            }],
            integration: vec![],
        };

        let review = to_review_story("story-29", &results, None);
        assert!(!review.can_accept);
        assert!(review.missing_categories.contains(&"integration".to_string()));
    }

    #[test]
    fn to_review_story_with_failures() {
        let results = StoryTestResults {
            unit: vec![TestCaseResult {
                name: "u1".to_string(),
                status: TestStatus::Fail,
                details: None,
            }],
            integration: vec![TestCaseResult {
                name: "i1".to_string(),
                status: TestStatus::Pass,
                details: None,
            }],
        };

        let review = to_review_story("story-29", &results, None);
        assert!(!review.can_accept);
        assert_eq!(review.summary.failed, 1);
    }

    #[test]
    fn load_upcoming_returns_empty_when_no_dir() {
        let tmp = tempfile::tempdir().unwrap();
        let root = tmp.path().to_path_buf();
        // No .story_kit directory at all
        let ctx = crate::http::context::AppContext::new_test(root);
        let result = load_upcoming_stories(&ctx).unwrap();
        assert!(result.is_empty());
    }

    #[test]
    fn load_upcoming_parses_metadata() {
        let tmp = tempfile::tempdir().unwrap();
        let upcoming = tmp.path().join(".story_kit/stories/upcoming");
        fs::create_dir_all(&upcoming).unwrap();
        fs::write(
            upcoming.join("31_view_upcoming.md"),
            "---\nname: View Upcoming\ntest_plan: pending\n---\n# Story\n",
        )
        .unwrap();
        fs::write(
            upcoming.join("32_worktree.md"),
            "---\nname: Worktree Orchestration\ntest_plan: pending\n---\n# Story\n",
        )
        .unwrap();

        let ctx = crate::http::context::AppContext::new_test(tmp.path().to_path_buf());
        let stories = load_upcoming_stories(&ctx).unwrap();
        assert_eq!(stories.len(), 2);
        assert_eq!(stories[0].story_id, "31_view_upcoming");
        assert_eq!(stories[0].name.as_deref(), Some("View Upcoming"));
        assert_eq!(stories[1].story_id, "32_worktree");
        assert_eq!(stories[1].name.as_deref(), Some("Worktree Orchestration"));
    }

    #[test]
    fn load_upcoming_skips_non_md_files() {
        let tmp = tempfile::tempdir().unwrap();
        let upcoming = tmp.path().join(".story_kit/stories/upcoming");
        fs::create_dir_all(&upcoming).unwrap();
        fs::write(upcoming.join(".gitkeep"), "").unwrap();
        fs::write(
            upcoming.join("31_story.md"),
            "---\nname: A Story\ntest_plan: pending\n---\n",
        )
        .unwrap();

        let ctx = crate::http::context::AppContext::new_test(tmp.path().to_path_buf());
        let stories = load_upcoming_stories(&ctx).unwrap();
        assert_eq!(stories.len(), 1);
        assert_eq!(stories[0].story_id, "31_story");
    }
}