package handlers

import (
	"database/sql"
	"encoding/json"
	"fmt"
	"net/http"

	"github.com/HoHD/PR-Helper/services"
	"github.com/gin-gonic/gin"
)

type GenerateHandler struct {
	db *sql.DB
}

func NewGenerateHandler(db *sql.DB) *GenerateHandler {
	return &GenerateHandler{db: db}
}

// Generate handles POST /api/repos/:id/generate — SSE streaming PR description generation.
func (h *GenerateHandler) Generate(c *gin.Context) {
	id := c.Param("id")

	// Get repo info
	var localPath string
	err := h.db.QueryRow(`SELECT local_path FROM repositories WHERE id = ?`, id).Scan(&localPath)
	if err == sql.ErrNoRows {
		c.JSON(http.StatusNotFound, gin.H{"error": "repository not found"})
		return
	}
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	// Parse request
	var req struct {
		Base string `json:"base" binding:"required"`
		Head string `json:"head" binding:"required"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "base and head are required"})
		return
	}

	// Set SSE headers
	c.Header("Content-Type", "text/event-stream")
	c.Header("Cache-Control", "no-cache")
	c.Header("Connection", "keep-alive")
	c.Header("X-Accel-Buffering", "no")
	c.Status(http.StatusOK)

	flusher, ok := c.Writer.(http.Flusher)
	if !ok {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "streaming not supported"})
		return
	}

	sendEvent := func(event string, data interface{}) {
		jsonData, err := json.Marshal(data)
		if err != nil {
			jsonData = []byte(`{"error":"failed to marshal event data"}`)
		}
		fmt.Fprintf(c.Writer, "event: %s\ndata: %s\n\n", event, jsonData)
		flusher.Flush()
	}

	// Update last_used
	h.db.Exec(`UPDATE repositories SET last_used = datetime('now') WHERE id = ?`, id)

	// Generate PR description
	pr, err := services.GeneratePR(h.db, localPath, req.Base, req.Head, sendEvent)
	if err != nil {
		sendEvent("error", map[string]interface{}{"message": err.Error()})
		return
	}

	// Save analysis to DB
	resultJSON, err := json.Marshal(pr)
	if err != nil {
		sendEvent("error", map[string]interface{}{"message": "marshal result: " + err.Error()})
		return
	}
	if _, err := h.db.Exec(`INSERT INTO analyses (repo_id, type, base_ref, head_ref, result) VALUES (?, 'pr_description', ?, ?, ?)`,
		id, req.Base, req.Head, string(resultJSON)); err != nil {
		sendEvent("error", map[string]interface{}{"message": "save analysis: " + err.Error()})
		return
	}
}