import { Change, diffLines } from 'diff'
import { Platform, getIcon } from 'obsidian'
import { useEffect, useState } from 'react'
import ContentEditable from 'react-contenteditable'

import { ApplyViewState } from '../../ApplyView'
import { useApp } from '../../contexts/AppContext'

export default function ApplyViewRoot({
	state,
	close,
}: {
	state: ApplyViewState
	close: () => void
}) {
	const acceptIcon = getIcon('check')
	const rejectIcon = getIcon('x')
	const excludeIcon = getIcon('x')

	const getShortcutText = (shortcut: 'accept' | 'reject') => {
		const isMac = Platform.isMacOS
		if (shortcut === 'accept') {
			return isMac ? '(⌘⏎)' : '(Ctrl+⏎)'
		}
		return isMac ? '(⌘⌫)' : '(Ctrl+⌫)'
	}

	const app = useApp()

	// Track which lines have been accepted or excluded
	const [diffStatus, setDiffStatus] = useState<Array<'active' | 'accepted' | 'excluded'>>([])
  
	const [diff] = useState<Change[]>(() => {
		const initialDiff = diffLines(state.oldContent, state.newContent)
		// Initialize all lines as 'active'
		setDiffStatus(initialDiff.map(() => 'active'))
		return initialDiff
	})
  
	// Store edited content for each diff part
	const [editedContents, setEditedContents] = useState<string[]>(
		diff.map(part => part.value)
	)

	const handleAccept = async () => {
		// Filter and process content based on diffStatus
		const newContent = diff.reduce((result, change, index) => {
			// Keep unchanged content, non-excluded additions, or excluded removals
			if ((!change.added && !change.removed) || 
				(change.added && diffStatus[index] !== 'excluded') || 
				(change.removed && diffStatus[index] === 'excluded')) {
				return result + editedContents[index];
			}
			return result;
		}, '')
		const file = app.vault.getFileByPath(state.file)
    if (!file) {
      throw new Error('File not found')
    }
    await app.vault.modify(file, newContent)
    if (state.onClose) {
      state.onClose(true)
    }
    close()
  }

  const handleReject = async () => {
    if (state.onClose) {
      state.onClose(false)
    }
    close()
  }

  const excludeDiffLine = (index: number) => {
    setDiffStatus(prevStatus => {
      const newStatus = [...prevStatus]
      // Mark line as excluded
      newStatus[index] = 'excluded'
      return newStatus
    })
  }

  const acceptDiffLine = (index: number) => {
    setDiffStatus(prevStatus => {
      const newStatus = [...prevStatus]
      // Mark line as accepted
      newStatus[index] = 'accepted'
      return newStatus
    })
  }

  const handleKeyDown = (event: KeyboardEvent) => {
    const modifierKey = Platform.isMacOS ? event.metaKey : event.ctrlKey;
    if (modifierKey) {
      if (event.key === 'Enter') {
        event.preventDefault();
        event.stopPropagation();
        handleAccept();
      } else if (event.key === 'Backspace') {
        event.preventDefault();
        event.stopPropagation();
        handleReject();
      }
    }
  }
  
  // Handle content editing changes
  const handleContentChange = (index: number, evt: { target: { value: string } }) => {
    const newEditedContents = [...editedContents];
    newEditedContents[index] = evt.target.value;
    setEditedContents(newEditedContents);
  }

  // Add event listeners on mount and remove on unmount
  useEffect(() => {
    const handler = (e: KeyboardEvent) => handleKeyDown(e);
    window.addEventListener('keydown', handler, true);
    return () => {
      window.removeEventListener('keydown', handler, true);
    }
  }, [handleAccept, handleReject]) // Dependencies for the effect

  return (
    <div id="infio-apply-view">
      <div className="view-header">
        <div className="view-header-left">
          <div className="view-header-nav-buttons"></div>
        </div>
        <div className="view-header-title-container mod-at-start">
          <div className="view-header-title">
            Applying: {state?.file ?? ''}
          </div>
          <div className="view-actions">
            <button
              className="clickable-icon view-action infio-approve-button"
              aria-label="Accept changes"
              onClick={handleAccept}
            >
              {acceptIcon && '✓'}
              Accept All {getShortcutText('accept')}
            </button>
            <button
              className="clickable-icon view-action infio-reject-button"
              aria-label="Reject changes"
              onClick={handleReject}
            >
              {rejectIcon && '✗'}
              Reject All {getShortcutText('reject')}
            </button>
          </div>
        </div>
      </div>

      <div className="view-content">
        <div className="markdown-source-view cm-s-obsidian mod-cm6 node-insert-event is-readable-line-width is-live-preview is-folding show-properties">
          <div className="cm-editor">
            <div className="cm-scroller">
              <div className="cm-sizer">
                <div className="infio-inline-title">
                  {state?.file
                    ? state.file.replace(/\.[^/.]+$/, '')
                    : ''}
                </div>

                {diff.map((part, index) => {
                  // Determine line display status based on diffStatus
                  const status = diffStatus[index]
                  const isHidden = 
                    (part.added && status === 'excluded') || 
                    (part.removed && status === 'accepted')
                  
                  if (isHidden) return null

                  return (
                    <div
                      key={index}
                      className={`infio-diff-line ${part.added ? 'added' : part.removed ? 'removed' : ''} ${status !== 'active' ? status : ''}`}
                    >
                      <div className="infio-diff-content-wrapper">
                        <ContentEditable
                          html={editedContents[index]}
                          onChange={(evt) => handleContentChange(index, evt)}
                          className="infio-editable-content"
                        />
                        {(part.added || part.removed) && status === 'active' && (
                          <div className="infio-diff-line-actions">
                            <button
                              aria-label="Accept line"
                              onClick={() => acceptDiffLine(index)}
                              className="infio-accept"
                            >
                              {acceptIcon && '✓'}
                            </button>
                            <button
                              aria-label="Exclude line"
                              onClick={() => excludeDiffLine(index)}
                              className="infio-exclude"
                            >
                              {excludeIcon && '✗'}
                            </button>
                          </div>
                        )}
                      </div>
                    </div>
                  )
                })}
              </div>
            </div>
          </div>
        </div>
      </div>
      <style>{`
        .infio-diff-content-wrapper {
          position: relative;
          width: 100%;
        }
        
        .infio-editable-content {
          width: 100%;
          min-height: 1.2em;
          padding: 4px;
          padding-right: 60px;
          border: 1px solid transparent;
          box-sizing: border-box;
        }

        .infio-editable-content:focus {
          outline: none;
          border-color: var(--interactive-accent);
          background-color: var(--background-primary);
        }
        
        .infio-diff-line-actions {
          position: absolute;
          right: 4px;
          top: 4px;
          display: flex;
          gap: 4px;
        }
        
        .infio-diff-line-actions button {
          padding: 2px 6px;
          border-radius: 4px;
          background: var(--background-secondary);
          border: 1px solid var(--background-modifier-border);
          cursor: pointer;
          opacity: 0.7;
          transition: opacity 0.2s;
        }
        
        .infio-diff-line-actions button:hover {
          opacity: 1;
        }
        
        .infio-accept {
          color: #26a69a;
        }
        
        .infio-exclude {
          color: #ef5350;
        }

        .infio-diff-line.added .infio-editable-content {
          background-color: rgba(0, 255, 0, 0.1);
          border-left: 3px solid #26a69a;
        }

        .infio-diff-line.removed .infio-editable-content {
          background-color: rgba(255, 0, 0, 0.1);
          border-left: 3px solid #ef5350;
          text-decoration: line-through;
        }

        .infio-diff-line.accepted .infio-editable-content {
          opacity: 0.7;
        }
      `}</style>
    </div>
  )
}