package handlers

import (
	"net/http"
	"strconv"
	"time"

	"github.com/go-chi/chi/v5"
	"xorm.io/xorm"

	"github.com/forgeo/forgebucket/internal/models"
)

type PipelineHandler struct {
	db *xorm.Engine
}

func NewPipelineHandler(db *xorm.Engine) *PipelineHandler {
	return &PipelineHandler{db: db}
}

// ListPipelines returns all pipeline definitions for a repository.
func (h *PipelineHandler) ListPipelines(w http.ResponseWriter, r *http.Request) {
	repoID, ok := h.repoID(w, r)
	if !ok {
		return
	}
	var pipelines []models.Pipeline
	if err := h.db.Where("repo_id = ?", repoID).Find(&pipelines); err != nil {
		jsonError(w, "could not list pipelines", http.StatusInternalServerError)
		return
	}
	if pipelines == nil {
		pipelines = []models.Pipeline{}
	}
	jsonOK(w, pipelines)
}

// ListRuns returns pipeline runs for a repository, most recent first.
func (h *PipelineHandler) ListRuns(w http.ResponseWriter, r *http.Request) {
	repoID, ok := h.repoID(w, r)
	if !ok {
		return
	}
	limit := 30
	if l, err := strconv.Atoi(r.URL.Query().Get("limit")); err == nil && l > 0 && l <= 100 {
		limit = l
	}
	var runs []models.PipelineRun
	if err := h.db.Where("repo_id = ?", repoID).Desc("id").Limit(limit).Find(&runs); err != nil {
		jsonError(w, "could not list runs", http.StatusInternalServerError)
		return
	}
	if runs == nil {
		runs = []models.PipelineRun{}
	}
	jsonOK(w, runs)
}

type runDetailResponse struct {
	models.PipelineRun
	Jobs []jobDetailResponse `json:"jobs"`
}

type jobDetailResponse struct {
	models.PipelineJob
	Steps []models.PipelineStep `json:"steps"`
}

// GetRun returns a run with its full job + step tree.
func (h *PipelineHandler) GetRun(w http.ResponseWriter, r *http.Request) {
	run, ok := h.lookupRun(w, r)
	if !ok {
		return
	}
	var jobs []models.PipelineJob
	h.db.Where("run_id = ?", run.ID).Asc("id").Find(&jobs)

	jobDetails := make([]jobDetailResponse, len(jobs))
	for i, job := range jobs {
		var steps []models.PipelineStep
		h.db.Where("job_id = ?", job.ID).Asc("seq").Find(&steps)
		if steps == nil {
			steps = []models.PipelineStep{}
		}
		jobDetails[i] = jobDetailResponse{PipelineJob: job, Steps: steps}
	}
	jsonOK(w, runDetailResponse{PipelineRun: *run, Jobs: jobDetails})
}

// GetJobLogs returns all log chunks for a job, ordered by step seq and chunk index.
func (h *PipelineHandler) GetJobLogs(w http.ResponseWriter, r *http.Request) {
	_, ok := h.lookupRun(w, r)
	if !ok {
		return
	}
	jobID, err := strconv.ParseInt(chi.URLParam(r, "jobID"), 10, 64)
	if err != nil {
		jsonError(w, "invalid job ID", http.StatusBadRequest)
		return
	}

	// Verify job belongs to this run.
	var job models.PipelineJob
	runID, _ := strconv.ParseInt(chi.URLParam(r, "runID"), 10, 64)
	if found, _ := h.db.Where("id = ? AND run_id = ?", jobID, runID).Get(&job); !found {
		jsonError(w, "job not found", http.StatusNotFound)
		return
	}

	var steps []models.PipelineStep
	h.db.Where("job_id = ?", jobID).Asc("seq").Find(&steps)

	type stepLogs struct {
		models.PipelineStep
		Logs []models.PipelineStepLog `json:"logs"`
	}
	result := make([]stepLogs, len(steps))
	for i, step := range steps {
		var logs []models.PipelineStepLog
		h.db.Where("step_id = ?", step.ID).Asc("chunk_index").Find(&logs)
		if logs == nil {
			logs = []models.PipelineStepLog{}
		}
		result[i] = stepLogs{PipelineStep: step, Logs: logs}
	}
	jsonOK(w, result)
}

// CancelRun marks a queued or running run as cancelled.
func (h *PipelineHandler) CancelRun(w http.ResponseWriter, r *http.Request) {
	run, ok := h.lookupRun(w, r)
	if !ok {
		return
	}
	if run.Status != "queued" && run.Status != "running" {
		jsonError(w, "run is not cancellable in its current state", http.StatusConflict)
		return
	}
	now := time.Now().UTC()
	run.Status = "cancelled"
	run.FinishedAt = &now
	if _, err := h.db.ID(run.ID).Cols("status", "finished_at").Update(run); err != nil {
		jsonError(w, "could not cancel run", http.StatusInternalServerError)
		return
	}
	// Cancel any queued jobs.
	h.db.Where("run_id = ? AND status = 'queued'", run.ID). //nolint:errcheck
		Cols("status").Update(&models.PipelineJob{Status: "cancelled"})
	jsonOK(w, run)
}

// RetryJob re-queues a failed job by resetting its status and re-publishing job.queued.
func (h *PipelineHandler) RetryJob(w http.ResponseWriter, r *http.Request) {
	run, ok := h.lookupRun(w, r)
	if !ok {
		return
	}
	jobID, err := strconv.ParseInt(chi.URLParam(r, "jobID"), 10, 64)
	if err != nil {
		jsonError(w, "invalid job ID", http.StatusBadRequest)
		return
	}
	var job models.PipelineJob
	if found, _ := h.db.Where("id = ? AND run_id = ?", jobID, run.ID).Get(&job); !found {
		jsonError(w, "job not found", http.StatusNotFound)
		return
	}
	if job.Status != "failed" && job.Status != "cancelled" {
		jsonError(w, "only failed or cancelled jobs can be retried", http.StatusConflict)
		return
	}

	job.Status = "queued"
	job.StartedAt = nil
	job.FinishedAt = nil
	h.db.ID(job.ID).Cols("status", "started_at", "finished_at").Update(&job) //nolint:errcheck

	// Reset step statuses.
	h.db.Where("job_id = ?", job.ID).Cols("status", "exit_code", "started_at", "finished_at"). //nolint:errcheck
		Update(&models.PipelineStep{Status: "queued"})

	// Also reset the run status if it was failed/cancelled.
	if run.Status == "failed" || run.Status == "cancelled" {
		run.Status = "running"
		run.FinishedAt = nil
		h.db.ID(run.ID).Cols("status", "finished_at").Update(run) //nolint:errcheck
	}

	jsonOK(w, job)
}

// ── Helpers ───────────────────────────────────────────────────────────────────

func (h *PipelineHandler) repoID(w http.ResponseWriter, r *http.Request) (int64, bool) {
	owner := chi.URLParam(r, "owner")
	repoName := chi.URLParam(r, "repo")
	var u models.User
	if found, _ := h.db.Where("username = ?", owner).Get(&u); !found {
		jsonError(w, "repository not found", http.StatusNotFound)
		return 0, false
	}
	var repo models.Repository
	if found, _ := h.db.Where("owner_id = ? AND name = ?", u.ID, repoName).Get(&repo); !found {
		jsonError(w, "repository not found", http.StatusNotFound)
		return 0, false
	}
	return repo.ID, true
}

func (h *PipelineHandler) lookupRun(w http.ResponseWriter, r *http.Request) (*models.PipelineRun, bool) {
	repoID, ok := h.repoID(w, r)
	if !ok {
		return nil, false
	}
	runID, err := strconv.ParseInt(chi.URLParam(r, "runID"), 10, 64)
	if err != nil {
		jsonError(w, "invalid run ID", http.StatusBadRequest)
		return nil, false
	}
	var run models.PipelineRun
	if found, _ := h.db.Where("id = ? AND repo_id = ?", runID, repoID).Get(&run); !found {
		jsonError(w, "run not found", http.StatusNotFound)
		return nil, false
	}
	return &run, true
}