package iop

import (
	"context"
	"errors"
	"fmt"
	"strings"
	"time"

	"git.toki-labs.com/toki/ariadne/internal/domain/errorrecord"
	"git.toki-labs.com/toki/ariadne/internal/domain/failure"
	"git.toki-labs.com/toki/ariadne/internal/domain/organization"
	"git.toki-labs.com/toki/ariadne/internal/domain/remediation"
	"github.com/google/uuid"
)

// Executor is the Ariadne-owned boundary for LLM and CLI work. Implementations
// may use IOP's native protocol without leaking that protocol into the domain.
type Executor interface {
	Start(context.Context, Request) (Execution, error)
	Events(
		context.Context,
		organization.ID,
		string,
		uint64,
	) (EventStream, error)
	Cancel(context.Context, organization.ID, string) error
}

type EventStream interface {
	Receive(context.Context) (Event, error)
	Close() error
}

type Intent string

const (
	IntentAnalyze     Intent = "analyze"
	IntentApplyChange Intent = "apply_change"
)

type RepositoryAccess string

const (
	RepositoryAccessReadOnly       RepositoryAccess = "read_only"
	RepositoryAccessIsolatedBranch RepositoryAccess = "isolated_branch"
)

const RuntimeAccessReadOnly = "read_only"

type Request struct {
	ExecutionID       string
	OrganizationID    organization.ID
	ProjectID         string
	IngestionSourceID string
	ErrorGroupID      string
	Intent            Intent
	Mode              remediation.Mode
	ProposalDigest    string
	Error             errorrecord.Event
	Repository        RepositoryTarget
	RuntimeTargets    []RuntimeTarget
	Policy            Policy
	Deadline          time.Time
}

type RepositoryTarget struct {
	RepositoryID       string
	WorkspaceReference string
	BaseRevision       string
}

type RuntimeTarget struct {
	EnvironmentID       string
	ConnectionReference string
}

type Policy struct {
	RepositoryAccess RepositoryAccess
	RuntimeAccess    string
	AllowMerge       bool
}

type Execution struct {
	ID        string
	StartedAt time.Time
}

type EventType string

const (
	EventStarted          EventType = "started"
	EventProgress         EventType = "progress"
	EventAnalysisResult   EventType = "analysis_result"
	EventChangeResult     EventType = "change_result"
	EventValidationResult EventType = "validation_result"
	EventCompleted        EventType = "completed"
	EventFailed           EventType = "failed"
	EventCancelled        EventType = "cancelled"
)

type Event struct {
	ExecutionID string
	Sequence    uint64
	Type        EventType
	Message     string
	Analysis    *AnalysisResult
	Change      *ChangeResult
	Validation  *ValidationResult
	Failure     *failure.Failure
	OccurredAt  time.Time
}

type AnalysisResult struct {
	Fixability     remediation.Fixability
	Report         string
	ProposalDigest string
}

type ChangeResult struct {
	Changed        bool
	Branch         string
	PatchReference string
}

type ValidationResult struct {
	Passed             bool
	Summary            string
	ArtifactReferences []string
}

func (request Request) Validate() error {
	var validationErrors []error
	if _, err := uuid.Parse(request.ExecutionID); err != nil {
		validationErrors = append(validationErrors, fmt.Errorf("execution id: %w", err))
	}
	if err := request.OrganizationID.Validate(); err != nil {
		validationErrors = append(validationErrors, fmt.Errorf("organization id: %w", err))
	}
	for field, value := range map[string]string{
		"project id":          request.ProjectID,
		"ingestion source id": request.IngestionSourceID,
		"error group id":      request.ErrorGroupID,
		"repository id":       request.Repository.RepositoryID,
	} {
		if _, err := uuid.Parse(value); err != nil {
			validationErrors = append(validationErrors, fmt.Errorf("%s: %w", field, err))
		}
	}
	if request.Intent != IntentAnalyze && request.Intent != IntentApplyChange {
		validationErrors = append(validationErrors, errors.New("execution intent is invalid"))
	}
	if _, err := remediation.ParseMode(string(request.Mode)); err != nil {
		validationErrors = append(validationErrors, err)
	}
	if err := request.Error.Validate(); err != nil {
		validationErrors = append(validationErrors, fmt.Errorf("error event: %w", err))
	}
	if request.Error.OrganizationID != request.OrganizationID ||
		request.Error.ProjectID != request.ProjectID ||
		request.Error.IngestionSourceID != request.IngestionSourceID {
		validationErrors = append(
			validationErrors,
			errors.New("error event scope does not match execution scope"),
		)
	}
	if strings.TrimSpace(request.Repository.WorkspaceReference) == "" {
		validationErrors = append(
			validationErrors,
			errors.New("repository workspace reference is required"),
		)
	}
	if strings.TrimSpace(request.Repository.BaseRevision) == "" {
		validationErrors = append(
			validationErrors,
			errors.New("repository base revision is required"),
		)
	}
	for index, target := range request.RuntimeTargets {
		if _, err := uuid.Parse(target.EnvironmentID); err != nil {
			validationErrors = append(
				validationErrors,
				fmt.Errorf("runtime target %d environment id: %w", index, err),
			)
		}
		if strings.TrimSpace(target.ConnectionReference) == "" {
			validationErrors = append(
				validationErrors,
				fmt.Errorf("runtime target %d connection reference is required", index),
			)
		}
	}
	if request.Policy.RuntimeAccess != RuntimeAccessReadOnly {
		validationErrors = append(
			validationErrors,
			errors.New("runtime access must be read-only"),
		)
	}
	if request.Policy.AllowMerge {
		validationErrors = append(
			validationErrors,
			errors.New("IOP must not receive merge permission"),
		)
	}
	switch request.Policy.RepositoryAccess {
	case RepositoryAccessReadOnly, RepositoryAccessIsolatedBranch:
	default:
		validationErrors = append(
			validationErrors,
			errors.New("repository access policy is invalid"),
		)
	}
	if request.Intent == IntentAnalyze &&
		request.Policy.RepositoryAccess != RepositoryAccessReadOnly {
		validationErrors = append(
			validationErrors,
			errors.New("analysis execution must use read-only repository access"),
		)
	}
	if request.Intent == IntentApplyChange &&
		request.Policy.RepositoryAccess != RepositoryAccessIsolatedBranch {
		validationErrors = append(
			validationErrors,
			errors.New("change execution must use an isolated branch"),
		)
	}
	switch request.Intent {
	case IntentAnalyze:
		if strings.TrimSpace(request.ProposalDigest) != "" {
			validationErrors = append(
				validationErrors,
				errors.New("analysis execution must not include a proposal digest"),
			)
		}
	case IntentApplyChange:
		if strings.TrimSpace(request.ProposalDigest) == "" {
			validationErrors = append(
				validationErrors,
				errors.New("change execution requires the authorized proposal digest"),
			)
		}
	}
	if request.Deadline.IsZero() {
		validationErrors = append(validationErrors, errors.New("execution deadline is required"))
	}
	return errors.Join(validationErrors...)
}

func (event Event) Validate() error {
	var validationErrors []error
	if _, err := uuid.Parse(event.ExecutionID); err != nil {
		validationErrors = append(validationErrors, fmt.Errorf("execution id: %w", err))
	}
	if event.OccurredAt.IsZero() {
		validationErrors = append(validationErrors, errors.New("event occurrence time is required"))
	}

	switch event.Type {
	case EventStarted, EventProgress, EventCompleted, EventCancelled:
	case EventAnalysisResult:
		if event.Analysis == nil {
			validationErrors = append(validationErrors, errors.New("analysis result is required"))
			break
		}
		if _, err := remediation.ParseFixability(string(event.Analysis.Fixability)); err != nil {
			validationErrors = append(validationErrors, err)
		}
		if strings.TrimSpace(event.Analysis.Report) == "" {
			validationErrors = append(validationErrors, errors.New("analysis report is required"))
		}
		if event.Analysis.Fixability == remediation.FixabilityFixable &&
			strings.TrimSpace(event.Analysis.ProposalDigest) == "" {
			validationErrors = append(
				validationErrors,
				errors.New("fixable analysis requires a proposal digest"),
			)
		}
		if event.Analysis.Fixability != remediation.FixabilityFixable &&
			strings.TrimSpace(event.Analysis.ProposalDigest) != "" {
			validationErrors = append(
				validationErrors,
				errors.New("only a fixable analysis may include a proposal digest"),
			)
		}
	case EventChangeResult:
		if event.Change == nil {
			validationErrors = append(validationErrors, errors.New("change result is required"))
			break
		}
		if event.Change.Changed &&
			(strings.TrimSpace(event.Change.Branch) == "" ||
				strings.TrimSpace(event.Change.PatchReference) == "") {
			validationErrors = append(
				validationErrors,
				errors.New("a changed result requires branch and patch references"),
			)
		}
		if !event.Change.Changed &&
			(strings.TrimSpace(event.Change.Branch) != "" ||
				strings.TrimSpace(event.Change.PatchReference) != "") {
			validationErrors = append(
				validationErrors,
				errors.New("an unchanged result must not include branch or patch references"),
			)
		}
	case EventValidationResult:
		if event.Validation == nil {
			validationErrors = append(validationErrors, errors.New("validation result is required"))
		} else if strings.TrimSpace(event.Validation.Summary) == "" {
			validationErrors = append(validationErrors, errors.New("validation summary is required"))
		}
	case EventFailed:
		if event.Failure == nil {
			validationErrors = append(validationErrors, errors.New("failure is required"))
		} else if err := event.Failure.Validate(); err != nil {
			validationErrors = append(validationErrors, fmt.Errorf("failure: %w", err))
		}
	default:
		validationErrors = append(validationErrors, errors.New("execution event type is invalid"))
	}

	payloadCount := 0
	for _, present := range []bool{
		event.Analysis != nil,
		event.Change != nil,
		event.Validation != nil,
		event.Failure != nil,
	} {
		if present {
			payloadCount++
		}
	}
	expectedPayloadCount := 0
	switch event.Type {
	case EventAnalysisResult, EventChangeResult, EventValidationResult, EventFailed:
		expectedPayloadCount = 1
	}
	if payloadCount != expectedPayloadCount {
		validationErrors = append(
			validationErrors,
			fmt.Errorf(
				"execution event payload count = %d, want %d for %q",
				payloadCount,
				expectedPayloadCount,
				event.Type,
			),
		)
	}

	return errors.Join(validationErrors...)
}