// Package ws provides WebSocket handling for the API
package ws

import (
	"encoding/json"
	"fmt"
	"path/filepath"

	"github.com/gorilla/websocket"
	"github.com/jfraeys/fetch_ml/internal/manifest"
	"github.com/jfraeys/fetch_ml/internal/worker/integrity"
)

// handleValidateRequest handles the ValidateRequest opcode (0x16)
func (h *Handler) handleValidateRequest(conn *websocket.Conn, payload []byte) error {
	// Parse payload format: [opcode:1][api_key_hash:16][mode:1][...]
	// mode=0: commit_id validation [commit_id_len:1][commit_id:var]
	// mode=1: task_id validation [task_id_len:1][task_id:var]
	if len(payload) < 18 {
		return h.sendErrorPacket(conn, ErrorCodeInvalidRequest, "payload too short", "")
	}

	mode := payload[17]

	if mode == 0 {
		// Commit ID validation (basic)
		if len(payload) < 20 {
			return h.sendErrorPacket(conn, ErrorCodeInvalidRequest, "payload too short for commit validation", "")
		}
		commitIDLen := int(payload[18])
		if len(payload) < 19+commitIDLen {
			return h.sendErrorPacket(conn, ErrorCodeInvalidRequest, "commit_id length mismatch", "")
		}
		commitIDBytes := payload[19 : 19+commitIDLen]
		commitIDHex := fmt.Sprintf("%x", commitIDBytes)

		report := map[string]interface{}{
			"ok":        true,
			"commit_id": commitIDHex,
		}
		payloadBytes, _ := json.Marshal(report)
		return h.sendDataPacket(conn, "validate", payloadBytes)
	}

	// Task ID validation (mode=1) - full validation with checks
	if len(payload) < 20 {
		return h.sendErrorPacket(conn, ErrorCodeInvalidRequest, "payload too short for task validation", "")
	}

	taskIDLen := int(payload[18])
	if len(payload) < 19+taskIDLen {
		return h.sendErrorPacket(conn, ErrorCodeInvalidRequest, "task_id length mismatch", "")
	}
	taskID := string(payload[19 : 19+taskIDLen])

	// Initialize validation report
	checks := make(map[string]interface{})
	ok := true

	// Get task from queue
	if h.taskQueue == nil {
		return h.sendErrorPacket(conn, ErrorCodeResourceNotFound, "task queue not available", "")
	}

	task, err := h.taskQueue.GetTask(taskID)
	if err != nil || task == nil {
		return h.sendErrorPacket(conn, ErrorCodeResourceNotFound, "task not found", "")
	}

	// Run manifest validation - load manifest if it exists
	rmCheck := map[string]interface{}{"ok": true}
	rmCommitCheck := map[string]interface{}{"ok": true}
	rmLocCheck := map[string]interface{}{"ok": true}
	rmLifecycle := map[string]interface{}{"ok": true}

	// Determine expected location based on task status
	expectedLocation := "running"
	if task.Status == "completed" || task.Status == "cancelled" || task.Status == "failed" {
		expectedLocation = "finished"
	}

	// Try to load run manifest from appropriate location
	var rm *manifest.RunManifest
	var rmLoadErr error

	if h.expManager != nil {
		// Try expected location first
		jobDir := filepath.Join(h.expManager.BasePath(), expectedLocation, task.JobName)
		rm, rmLoadErr = manifest.LoadFromDir(jobDir)

		// If not found and task is running, also check finished (wrong location test)
		if rmLoadErr != nil && task.Status == "running" {
			wrongDir := filepath.Join(h.expManager.BasePath(), "finished", task.JobName)
			rm, _ = manifest.LoadFromDir(wrongDir)
			if rm != nil {
				// Manifest exists but in wrong location
				rmLocCheck["ok"] = false
				rmLocCheck["expected"] = "running"
				rmLocCheck["actual"] = "finished"
				ok = false
			}
		}
	}

	if rm == nil {
		// No run manifest found
		if task.Status == "running" || task.Status == "completed" {
			rmCheck["ok"] = false
			ok = false
		}
	} else {
		// Run manifest exists - validate it

		// Check commit_id match
		taskCommitID := task.Metadata["commit_id"]
		if rm.CommitID != "" && taskCommitID != "" && rm.CommitID != taskCommitID {
			rmCommitCheck["ok"] = false
			rmCommitCheck["expected"] = taskCommitID
			ok = false
		}

		// Check lifecycle ordering (started_at < ended_at)
		if !rm.StartedAt.IsZero() && !rm.EndedAt.IsZero() && !rm.StartedAt.Before(rm.EndedAt) {
			rmLifecycle["ok"] = false
			ok = false
		}
	}

	checks["run_manifest"] = rmCheck
	checks["run_manifest_commit_id"] = rmCommitCheck
	checks["run_manifest_location"] = rmLocCheck
	checks["run_manifest_lifecycle"] = rmLifecycle

	// Resources check
	resCheck := map[string]interface{}{"ok": true}
	if task.CPU < 0 {
		resCheck["ok"] = false
		ok = false
	}
	checks["resources"] = resCheck

	// Snapshot check
	snapCheck := map[string]interface{}{"ok": true}
	if task.SnapshotID != "" && task.Metadata["snapshot_sha256"] != "" {
		// Verify snapshot SHA
		dataDir := h.dataDir
		if dataDir == "" {
			dataDir = filepath.Join(h.expManager.BasePath(), "data")
		}
		snapPath := filepath.Join(dataDir, "snapshots", task.SnapshotID)
		actualSHA, _ := integrity.DirOverallSHA256Hex(snapPath)
		expectedSHA := task.Metadata["snapshot_sha256"]
		if actualSHA != expectedSHA {
			snapCheck["ok"] = false
			snapCheck["actual"] = actualSHA
			ok = false
		}
	}
	checks["snapshot"] = snapCheck

	report := map[string]interface{}{
		"ok":     ok,
		"checks": checks,
	}
	payloadBytes, _ := json.Marshal(report)
	return h.sendDataPacket(conn, "validate", payloadBytes)
}